145
FXUS63 KDVN 061438
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
838 AM CST Tue Dec 6 2016
.UPDATE...
Issued at 836 AM CST Tue Dec 6 2016
Cold front pushing across eastern IA this morning will rapidly dissipate
the dense fog/low stratus that`s ahead of the front. The front should
be east of the dvn cwa by noon with sunshine and brisk winds this
afternoon over much of the cwa.
&&
.SYNOPSIS...
Issued at 312 AM CST Tue Dec 6 2016
At 230 AM CST...areas of fog and low clouds cover the region with temperatures
around freezing north to the mid 30s south. A cold front with scattered
flurries just behind the front north of I-80 is approaching northwest
sections of the area. AWIPS distance-time feature supports the front
with clearing conditions will pass through the area by 11 AM with any
flurries along and north of highway 30. Colder and drier air will continue
into the region the few days.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 312 AM CST Tue Dec 6 2016
Short term forecast confidence assessment...good or above average with
main issue the dissipating fog and if temperatures start falling by
afternoon. Area highs and lows should be within 3 degrees of forecast.
Today...cold front should pass from west to east roughly between 6 AM
and 11 AM with fog rapidly dissipating and clearing skies. Highs most
locations will tend to be mid day all but far east as falling temperatures
by afternoon with 20s most locations by sunset. West to northwest winds
of 10 to 20+ MPH will be the case late morning through the afternoon.
Tonight...fair skies with increasing clouds late and continued brisk
northwest winds. Mins to fall into teens northwest to mid 20s southeast.
This will mark the coldest night of the early winter season with wind
chill values falling to 5 to 15 degrees above zero by daybreak.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 312 AM CST Tue Dec 6 2016
Zonal to NW H5 flow will dominate the long term period. A number of
disturbances will move through this flow leading to a highly dynamic
forecast period. Highly energetic jet across the US along with the
H5 flow will lead to an active forecast period with high run to run
variability in the models. As a result, overall confidence in
forecast is low.
The beginning of the long term features a vort max rotating around
cyclonic flow across our area. Previous forecast had light snow for
southern two tiers of counties. Latest guidance suggests that the
threat for snow across this area continues to diminish. If it
wasn`t for the GEM and ECMWF, we would have a dry forecast. Think
that the next run of the blends will remove this schc pop for the
southernmost tier of counties. The main story will be the winter
temperatures across the area. Nighttime wind chills will be around
0 for most of the area Wednesday and Thursday night as Arctic air
makes its return to the Upper Mississippi River valley. Latest run
of guidance continues H85 temps in the -12 to -14C realm, so little
change to temps this shift.
Into this weekend, Friday night looks as though the chance for snow
returns to the area as a clipper type system overruns H85 WAA. The
GFS and GEM produce QPF across the northern CWA. The ECMWF does
not. So model inconsistencies begin the weekend. The GEM and GFS
have a stronger H5 wave eject out of the Rockies and produces
another round of snow for Saturday night across the area. The ECMWF
does not have this wave. Current forecast has chance pops across
the area. That said, there is definitely more time for this to
change. What does seem more certain is the well-advertised cold air
to end the workweek.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
ISSUED AT 536 AM CST Tue Dec 6 2016
LIFR/IFR conditions in low clouds and fog will give way rapidly to
VFR conditions with clearing skies between 06/13Z and 06/15Z behind
a cold front. Fair skies and VFR will continue through the period
with west to northwest winds of 10 to 15+ MPH.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Dense Fog Advisory until 10 AM CST this morning for Cedar-
Clinton-Dubuque-Jackson-Jones-Muscatine-Scott.
IL...Dense Fog Advisory until 10 AM CST this morning for Bureau-
Carroll-Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-
Stephenson-Whiteside.
MO...NONE.
&&
$$
UPDATE...Haase
SYNOPSIS...Nichols
SHORT TERM...Nichols
LONG TERM...Gibbs
AVIATION...Nichols